Gear train with three planetary gear sets

ABSTRACT

Gear train arrangements for transmitting a power from a driving source to a driven member at more than three speeds in one direction and another speed in the opposite direction, the gear train arrangements using basically three planetary gear sets and at least five friction elements such as clutches and brakes which are selectively actuated to selectively engage the rotary members of the three planetary gear sets to deliver an output power at the above said speeds. The gear train arrangements are specifically adapted for use in an automatic transmission system of a motor vehicle using a torque converter or fluid coupling.

United States Patent 1 Mori et a1.

[ GEAR TRAIN WITH THREE PLANETARY GEAR SETS [75] Inventors: Yoichi Mori, Yokohama; Nobuo Okazaki, Chigasaki; Kunio Ohtsuka; Tetsuya Iijima, both of Tokyo, all of Japan [73] Assignee: Nissan Motor Company, Limited,

Yokohama City, Japan [22] Filed: Sept. 13, 1972 [21] Appl. No.: 288,549

Related US. Application Data [62] Division of Seri No. 30,496, April 21, 1970, Pat. No.

[52] US. Cl. 74/759 [51] Int. Cl. F16h 57/10 [58] Field of Search 74/759 [56] References Cited UNITED STATES PATENTS 3,067,632 12/1962 Foerster et al 74/759 July 23, E974 3,483,771 12/1969 v Forster et al. 74/759 Primary Examinep-Samuel Scott Assistant Examiner-J. Reep Attorney, Agent, or Firm-DePaoli & OBrien [57] ABSTRACT Gear train arrangements for transmitting a power from a driving source to a driven member at more than three speeds in one direction and another speed in the opposite direction, the gear train arrangements using basically three planetary gear sets and at least five friction elements such as clutches and brakes which are selectively actuated to selectively engage the rotary members of the three planetary gear sets to deliver an output power at the above said speeds. The gear train arrangements are specifically adapted for use in an automatic transmission system of a motor vehicle using a torque converter or fluid coupling.

4 Claims, 37 Drawing Figures PATENTEB 3.824.876

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sum 15 or 15 GEAR TRAIN WITH THREE PLANETARY GEAR SETS This is a division, of application Ser. No. 30,496, filed Apr. 21, 1970, now US. Pat. No. 3,701,293.

It relates to gear train arrangements for a transmission system of a motor vehicle and, more par-- ticularly, to gear train arrangements of planetary gear type adapted to provide basically four forward and one reverse vehicle speeds.

A usual gear train arrangement using a planetary gear system is made up of a combination of one or more, similar or different, planetary gear sets each having one or more planet pinions and is operated through actuation of friction elements such as clutches and brakes which are arranged to attain a desired combination of gear ratios. Typical of such gear train arrangement is the one that uses three simple planetary gear sets which are combined together to provide three forward and one reverse vehicle speeds. (It may be noted that the term simple" planetary gear set as herein used is intended to refer to a planetary gear set having a single planet pinion.)

Foremost of the practical requirements of a gear train arrangement to attain an increased number of vehicle speeds is a wide selection of the combinations of gear ratios, which requirement, however, is reflected by an increased number of component parts of the gear train arrangement and complicated gear shifting operations.

In order that the gear train be snugly accommodated within a limited space in the transmission system, every component of the planetary gear system should be as small in dimensions as possible. From the view point of production economy, moreover, it is desired that the number of the component parts of the gear train be reduced to a minimum and that the parts corresponding in function be fabricated to be common in geometry to one another so as to permit of quantity production. Another important requirement of the gear train of a transmisson system is the ease of gear shifting operations.

It is, therefore, an object of the invention to provide gear train arrangements adapted to provide basically four forward and one reverse vehicle speeds.

Another object is to provide gear train arrangements providing essentially four forward and one reverse vehicle speeds with wide selection of the combinations of gear ratios.

Still another object is to provide gear train arrangements providing four, or even more, forward and one reverse vehicle speeds, which arrangements are constructed with a practically minimum number of component parts and nevertheless can provide practically any desired combination of gear ratios.

Still another object is to provide gear train arrangements that are suited for quantity production.

Still another object is to provide gear train arrangements providing four, or even more, forward and one reverse vehicle speeds with utmost ease of gear shifting operations.

In order to achieve these and other objects, the invention proposes to use various combinations of basically three substantially identically sized planetary gear sets which are operated by means of two or three clutches and two or three brakes. The gear train arrangements using such combinations can be readily modified with incorporation of additional minor arrangements into those providing five or six forward and. one reverse vehicle speeds.

In the drawings:

FIGS. 1 to 8 are sectional views schematically showing various preferred embodiments of the invention, each of which embodiments uses three planetary gear sets with two clutches and three brakes to provide four forward and one reverse vehicle speeds;

FIG. 9 is similar to FIGS. 1 to 8 but shows other embodiment using three planetary gear sets with three clutches and two brakes to provide four forward and one reverse vehicle speeds;

FIGS. 10, 11, and 12 are views illustrating still other embodiments using three planetary gear sets with three clutches and three brakes to provide four forward and one reverse vehicle speeds;

FIG. 13 is a view illustrating still another embodiment using three planetary gear sets with three clutches and three brakes to provide five forward and one reverse vehicle speeds;

FIG. 14 is a view illustrating still another embodiment using four (including one auxiliary) planetary gear sets with three clutches and four brakes to provide four forward and one reverse vehicle speeds;

FIG. 15 is a view illustrating still another embodiment using four (including one auxiliary) planetary gear sets with two clutches and three brakes to provide five forward and one reverse vehicle speeds;

FIG. 16 is a view illustrating still another embodiment using four (including one auxiliary) planetary gear sets with three clutches and four brakes to provide six forward and one reverse vehicle speeds;

FIG. 17 is a view illustrating still another embodiment using four planetary gear sets with three clutches and five brakes to provide an overdrive from the fourth speed;

FIGS. 1a to 16a are diagrams each showing the different revolution speeds of the individual rotary members of the planetary gear sets used in the embodiment illustrated in the corresponding figure out of FIGS. 1 to 16; and

FIGS. lb, 4b, 6b, 7b, 8b, 9b and 10b are views each showing a modification of the embodiment illustrated in the corresponding figure without the subscript.

Corresponding reference numerals and characters represent like members in all the figures.

It may be noted in regard to the drawings that only the upper half of each gear train arrangement is herein shown for simplicity of illustrationbecause the gear train arrangement is generally symmetrical with respect to the input and output shafts.

First referring to FIG. 1, the gear train according to one embodiment of the invention is, as customary, connected at one end with an engine through an input shaft 10 and a torque converter or fluid coupling (not shown) and at the other end with a differential (not shown) through an output shaft 11 of the transmission system.

The gear train as shown includes a first, second and third planetary gear setsl'2, l3 and 14, all of which are constructed as simple planetary gear sets which are fabricated to be substantially identical in geometry with each other.

The first planetary gear set 12 comprises an outer ring gear R,, a planet pinion P meshing with the outer ring gear, and a sun gear S meshing with the planet pinion. The second planetary gear set 13 similarly comprises an outer ring gear R a planet pinion P meshing with the ring gear, and a sun gear 8, meshing with the planet pinion. The third planetary gear set 14 also similarly comprises an outer ring gear R a planet pinion P meshing with the ring gear, and a sun gear S meshing with the planet pinion. The planet pinions P,, P and P are carried on and revolved by pinion carriers 15, 16 and 17, respectively. The ring gears, pinion carriers and sun gears are all rotatable about a common axis which is in line with the axes of the pinion carriers. More detailed discussion on the constructions and motions of the planetary gear set per se is herein omitted because they are well known in the art.

The ring gear R, of the first planetary gear set 12 is constantly connected to and rotatable with the planet pinion P of the second planetary gear set 13 through the pinion carrier which forms part of a drum 18. The sun gears S, and S of the first and second planetary gear sets 12 and 13, respectively, are constantly conholds the pinion carrier 15 stationary. The drum 18 interconnecting the ring gear R, and pinion carrier 16 coacts with a second band brake B which, when applied, holds both the ring gear R, and pinion carrier 16 stationary. The dru rn 2 1 interconnecting the ring gear R and sun gear 8,, coacts with a third band brake B, which, when applied, holds both the ring gear R and sun gear S stationary.

Two clutches C, and C are provided to selectively connect the ring gear R to the drum 21 and the input shaft 10, respectively.

Now, it is well known in the art that, assuming the revolution speeds of a ring gear, sun gear and pinion carrier of a given planetary gear set are Nr, Ns and Np, respectively, and the ratio of the number of teeth of the sun gear to the number of teeth of the ring gear is a, then the following equation holds:

Thus, for the planetary gear sets 12, 13 and 14, the following equations can be derived:

where the subscripts l, 2 and 3 represent the first, second and third planetary gear sets 12, 13 and 14, respectively.

In consideration of the constant connections between some of the rotary members of the planetary gear sets, the following equations hold:

NS N8 Nr Np21 and Nrg NS3.

'The speeds Ns, and Np, are equal to the revolution speeds of the input and output shafts 10 and 11, respectively.

These mathematical relations between the revolution speeds of the individual rotary members of the plane-- tary gear sets can be graphically illustrated in FIG. la, wherein points L, M and N are given on a line 00' in such a manner that the following relations are maintained:

OL/LM 01,, ON/NO a and O'L/LO 01 Thus, the points 0, L, M, N and 0' stand for the relations between those individual rotary members of the planetary gear sets which are respectively shown below these points. The speed vector of each rotary member of the planetary gear sets is indicated by a length from the respective point 0, L, M, N or O on a line extending therefrom.

When, in operation, the first speed is to be selected, the second clutch C is coupled and the first brake B, applied. The ring gear R of the third planetary gear set 14 now rotates with the input shaft 10 and th e p in i o n carrier 15 is held stationary, so that tfi following equations hold:

Ns Nr and Np, 0.

In this condition, the sun gear S, is rotated directly by the input shaft 10 with the pinion carrier 15 held stationary so that the ring gear R, and the pinion carrier 16 of the planet pinion P rotate at a speed corresponding to a vector NN, in FIG. 1a. With the sun gear S rotating with the input shaft 10, the ring gear R2 and the sun gear 5;, rotate at a speed corresponding to a vector OO,. The ring gear R rotating with the input shaft and the sun gear 8;, rataimg'at a speed corrsitz niwfl 1 the Pinion carrier 17 Qflh planet pinion P rotates at speed corresponding tolls, providing a gear ratio for the first forward vehicle speed.

The gear ratio establishing the first speed thus delivered from the output shaft 11 is thus expressed as:

Ns,/Nc 1 (1 /1 04 11 txyoz; (l 04 When the vehicle speed is to be shifted from the first to the second speed, then the first brake B, is released and instead the second brake B is applied with the second clutch C kept coupled. Thus:

With the brake B applied, the pinion carrier 16 is held stationary and the sun gear 8;, rotates with the input shaft 10 so that the ring gear R and the sun gear 5;, are rotated at a speed corresponding to a vector O'OL in FIG. la. With the clutch C coupled, the ring gear 5;, rotates with the input shaft 10 so that the pinion carrier 17 of the planet pinion P rotates at a speed corresponding to a vector LLg providing a gear ratio for Nr- N83 0 and Nr N5 With the brake 8,, applied and the clutch C coupled, the sun gear 8;, is held stationary and the ring gear R rotates with the input shaft 10 so that the pinion carrier 17 of the planet pinion P rotates at a speed corresponding to a vector LL which provides a gear ratio to establish the third forward speed.

The gear ratio for the third speed is thus expressed as:

brake is kept released. The gear ratios indicated in the parentheses are derived on the assumption that a, a a 0.45. (This will apply to all the tables which are hereinafter presented.)

TABLE I 1 2 1 2 .1 Gear Ratios Forward lst (How/l l-a 'a or,'a l+cr 133 2nd (l+01 -,)/(la 'a 132 3rd H121 145 4th 1 1 n Reverse (-2.22)

When the speed is to be shifted from the third to the fourth speed, then the third brake B is released and the first clutch C, coupled with the second clutch C kept coupled. Thus:

Nr Nr =Ns Ns, /Np 1 When the vehicle is to be moved backwardly, the first clutch C, is coupled and the second brake B applied. Thus:

Nr Nr and Nr, Np 0.

With the brake 8, applied and the sun gear S rotating with the input shaft 10, the ring gear R and the sun gear S rotate at a speed corresponding to a vector OO Since, in this instance, the clutch C, is coupled, the ring gear R also rotates at a speed equal to the speed of the ring gear R and sun gear 8,. Both the ring gear R and sun gear S rotating at the speed corresponding to OO the planetary gear set 14 rotates in its entirety at this speed. The output shaft 11 is thus rotated at a speed corresponding to LL: in a direction opposite to the rotation of the input shaft 10.

The gear ratio for the reverse speed thus established is thus expressed as:

The conditions of the clutches and brakes for the different vehicle speeds and the gear ratios attained under these conditions are tabulated in Table I, wherein the sign refers to that the related clutch or brake is actuated and the sign refers to that the clutch or and actuating another one of them.

FIG. 2 illustrates another form of the gear train according to the invention. The gear train is constructed so as to provide four forward and one reverse speeds with use of three identical planetary gear sets 12, 13

and 14 which are operated by two clutches C, and C and three band brakes B,, B and B The first clutch C, is linked on the one hand with the input shaft 10 of the transmission and on the other with the ring gear R, of the first planetary gear set 12. The second clutch C which is also linked with the input shaft 10, is linked with both the sun gears S, and S of the first and second planetary gear sets 12 and 13, re-

spectively, through a drum 24 for the first band brake B,. The sun gears S, and S are as a result constantly connected together and rotatable with each other. The planet pinion P, of the first planetary gear set 12 is constantly connected to and rotatable with the ring gear R of the second planetarys gear set 13, sun gear 5;, of the third planetary gear set 14, and output shaft 11 of the transmission through the pinion carrier 15 and an intermediate shaft 25. The planet pinion P, of the second planetary gear set 13 is constantly connected to and rotatable with the planet pinion P of the third planetary TABLE II Gear Ratios Forward i TABLE II Continued C, C B, B B Gear Ratios 3rd I'HI, (L45) 4th l (1.00)

Rev. l/01- 2.22)

i When the first forward speed is selected, the clutch C, is coupled and the brake 8, applied. In this instance, the operations of the individual rotary members will be easily understood if it is assumed that the output shaft 11 is first rotated to impart a rotational effort to the input shaft 10, conversely to the actual operation. Thus, if the output shaft 11 is rotated at a speed corresponding to a vector AA, in FIG. 2a, then the ring gear R and the pinion carrier 15 of the planet pinion P, will rotate at the same speed as the output shaft 11. With the brake B applied, the planet pinion P is held stationary so that the sun gears S and S, rotate at a speed corresponding to a vector O'O,. Such rotation of the sun gear S, and the pinion carrier 15 (which revolves at a speed equal to the revolution speed of the output shaft 11) will dictate the speed at which the ring gear R, of the first planetary gear set 12 rotates as represented by a vector '0 in FIG. 2a. The driving force is actually carried to the input shaft 10, not to the output shaft 11, so that the flow of rotation is exactly inverse from that discussed above. Thus, it is apparent that the first speed corresponds with the vector LL,, in FIG 20.

When the speed is shifted from the first to the second speed, then the brake B is released and the brake B is applied with the clutch C, kept coupled. Here, it is also assumed that the driving force is initially trans- .ferred to the output shaft 11. If the output shaft 11 is rotated at a speed corresponding to a vector LL in FIG. 2a, the sun gear 8;, rotates with the output shaft 11. The ring gear R being held stationary with the brake 8, applied, the pinion carriers 17 and 16 rotate at a speed corresponding to a vector MM,. Since, in this instance, the ring gear R, rotates with theoutput shaft 11 at a speed corresponding to the vector LLZ, the sun gears S and S, rotate at a speed corresponding to the vector 00,. The planet pinion P, is rotated with the pinion carrier rotating with the output shaft 11 so that the ring gear R, will rotate at a speed corresponding to the vector 00,, in FIG. 2a. The actual operations of the planetary gear sets are exactly converse from those discussed above but, anyway, it is apparent that the second speed corresponds to the vector LL in FIG. 20.

When the speed is shifted from the second to the third speed, the brake B, in lieu of the brake B is now applied with the clutch C, kept coupled, so that the sun gears S, and 8,, are held stationary and the ring gear R, rotates with the input shaft 10. The pinion carrier 15 supporting the planet pinion P,, therefore, rotates at :1 speeds corresponding to a vector LL, providing a gear ratio for the third forward speed.

When the speed is further shifted up from the third to the fourth speeds, all the brakes are released and the clutches are coupled so that the first planetary gear set 12 rotates in its entirety at the same speed as the input shaft 10. The speed of the input shaft 10 is in this manner transferred to the output shaft 11 as it is.

For effecting the reverse movement of the vehicle, the clutch C is coupled and the brake B applied. The sun gear S now rotates with the input shaft 10 with the pinion carrier 15 held stationary so that the ring gear R rotates at a speed corresponding to a vector LL, which provides a gear ratio to establish the reverse speed.

It will now be appreciated that the gear train of FIG. 2 is, similarly to that of FIG. 1, adapted to provide ease of gear shifting operations because the gear ratios can be changed merely by releasing only one of the clutches and brakes and actuating another one of them.

FIG. 3 illustrates still another form of the gear train according to the invention constructed to provide four forward and one reverse speeds. The gear train also has three identical planetary gear sets 12, 13 and 14 with two clutches C, and C and three brakes B,, B and B,,, as shown.

The first clutch C, is linked on one side with the input shaft 10 and on the other with the ring gear R, of the first planetary gear set 12 through a drum 28 of the first band brake B,. The second clutch C is linked on one side with the input shaft 10 and on the other with the sun gears 8,, S and S of the first, second and third planetary gear sets 12, 13 and 14, respectively, through an intermediate shaft 29. The sun gears S,, S, and S are thus constantly connected to each other and rotatable with the input shaft 10 when the clutch C is coupled. The pinion carrier 15 of the planet pinion P, of the first planetary gear set 12 is constantly connected to and rotatable with the ring gear R of the second planetary gear set 13 through a drum 30 for the second hand brake B The pinion carrier 16 of the planet pinion P of the second planetary gear set 13 is constantly connected to and rotatable with the ring gear R 3 of the third planetary gear set 14 and is linked with the third brake B, through a drum 31. The pinion carrier 17 of the planet pinion P of the third planetary gear set 14 is connected to the output shaft 11. A one-way brake 32 is provided to prevent the pinion carrier 16 and ring gear R, from rotating in a direction opposite to the rotation of the input shaft 10.

Np, Nr Np, Nr and Ns, Ns Ns The conditions of the clutches and brakes for the different vehicle speeds and the gear ratios attained in these conditions are tabulated in Table III. 

1. A change speed gear train for transmitting rotary drive from a rotary drive source to a driven member, said change speed gear train comprising:
 1. an input shaft connected to said source to be rotated thereby in one given direction only;
 2. an output shaft connected to said driven member;
 3. a first planetary gear set;
 4. a second planetary gear set;
 5. a third planetary gear set;
 6. each of said planetary gear sets comprising firstly a rotary member in the form of an outer ring gear which is internally toothed, secondly a rotary member in the form of a sun gear which is externally toothed, thirdly a planet pinion meshing both with said ring gear and with said sun gear and fourthly a rotary member in the form of a planet carrier rotatably carrying the planet pinion;
 7. said input shaft, said output shaft and said rotary members of said first, second and third planetary gear sets all being rotatable about a common axis;
 8. said change speed gear train also comprising a plurality of mechanical linkages each constantly connecting together a respective pair of said rotary members to prevent rotation other than synchronous rotation of the respective pair of rotary members;
 9. a first clutch and a second clutch each selectively operable to connect said input shaft to at least one respective one of said rotary members;
 10. a first brake, a second brake and a third brake each selectively operable to brake at least one respective one of said rotary members against rotation about said axis;
 11. said change speed gear train producing, upon rotation of said input shaft in said given direction, rotation of said output shaft selectively in said given direction, rotation of said output shaft selectively in said given direction with at least three different speeds and also selectively in the opposite direction with one speed;
 12. further comprising a one-way brake preventing said pinion carriers of said first and second planetary gear sets and the ring gear of said third planetary gear set from rotating in the direction opposite to the said given direction of rotation of said input shaft;
 13. the sun gears of said second and third planetary gear sets are connected constantly to each other;
 2. an output shaft connected to said driven member;
 2. said third clutch is connected between said input shaft on the one hand and the planet carriers of said first and second planetary gear sets and the ring gear of said third planetary gear set on the other hand;
 2. A gear train as claimed in claim 1 and further comprising a third clutch wherein:
 2. a fourth brake operatively connected to the sun gear of said fourth planetary gear set, said first clutch being couplable and said fourth brake being operable for selecting another speed lower than the first speed in said given direction, whereby said rotational power which said input shaft receives from said driving source can be transmitted to said driven member at six different speeds in said given direction and one speed in the opposite direction through actuation of said clutches and brakes.
 2. a fourth brake operatively connected to the sun gear of said fourth planetary gear set; and
 3. said first clutch being couplable and said fourth brake being operable for selecting another speed lower than the first speed in said given direction, whereby said rotational power which said input shaft receives from said driving source can be transmitted to said driven member at four different speeds in said given direction and one speed in the opposite direction through actuation of said clutches and brakes.
 3. said second clutch and third clutch are operable to select a direct speed; and
 3. A gear train as claimed in claim 1 and further comprising:
 3. a first planetary gear set;
 4. a second planetary gear set;
 4. said third clutch and said first brake are operable to select an overdrive speed in said given direction.
 4. A gear train as claimed in claim 2 and further comprising:
 5. a third planetary gear set;
 6. each of said planetary gear sets comprising firstly a rotary member in the form of an outer ring gear which is internally toothed, secondly a rotary member in the form of a sun gear which is externally toothed, thirdly a planet pinion meshing both with said ring gear and with said sun gear and fourthly a rotary member in the form of a planet carrier rotatably carrying the planet pinion;
 7. said input shaft, said output shaft and said rotary members of said first, second and third planetary gear sets all being rotatable about a common axis;
 8. said change speed gear train also comprising a plurality of mechanical linkages each constantly connecting together a respective pair of said rotary members to prevent rotation other than synchronous rotation of the respective pair of rotary members;
 9. a first clutch and a second clutch each selectively operable to connect said input shaft to at least one respective one of said rotary members;
 10. a first brake, a second brake and a third brake each selectively operable to brake at least one respective one of said rotary members against rotation about said axis;
 11. said change speed gear train producing, upon rotation of said input shaft in said given direction, rotation of said output shaft selectively in said given direction, rotation of said output shaft selectively in said given direction with at least three different speeds and also selectively in the opposite direction with one speed;
 12. further comprising a one-way brake preventing said pinion carriers of said first and second planetary gear sets and the ring gear of said third planetary gear set from rotating in the direction opposite to the said given direction of rotation of said input shaft;
 13. the sun gears of said second and third planetary gear sets are connected constantly to each other;
 14. The pinion carrier of said third planetary gear set is connected constantly to said output shaft;
 14. The pinion carrier of said third planetary gear set is connected constantly to said output shaft;
 15. said first clutch being operatively connected between said input shaft and the sun gear of said first planetary gear set and couplable for selecting the one speed in the direction opposite to said normal direction;
 16. said second clutch being operatively connected between said input shaft on the one hand and the sun gears of said second and third planetary gear sets and couplable for selecting the first, second, and third speeds in said given direction;
 17. said first brake being operatively connected between said first clutch and to the sun gear of said first planetary gear set and operable for selecting the third speed in said given direction;
 18. said second brake being operatively connected to the pinion carriers of said first and second planetary gear sets and the ring gear of the third planetary gear set and operable for selecting the one speed in said opposite direction; and
 19. said third brake being operatively connected to the ring gear of said second planetary gear set and operable for selecting the second speed in said given direction.
 15. said first clutch being operatively connected between said input shaft and the sun gear of said first planetary gear set and couplable for selecting the one speed in the direction opposite to said normal direction;
 16. said second clutch being operatively connected between said input shaft on the one hand and the sun gears of said second and third planetary gear sets and couplable for selecting the first, second, and third speeds in said given direction;
 17. said first brake being operatively connected between said first clutch and to the sun gear of said first planetary gear set and operable for selecting the third speed in said given direction;
 18. said second brake being operatively connected to the pinion carriers of said first and second planetary gear sets and the ring gear of the third planetary gear set and operable for selecting the one speed in said opposite direction; and
 19. said third brake being operatively connected to the ring gear of said second planetary gear set and operable for selecting the second speed in said given direction. 